X-ray tube.



J. H. SNIVELY.

X-RAY TUBE.

APPLIOATION FILED 00124, 1911.

1,048,433. Patented Dec.24,1912.

UNITED s'rATEsrarENT oFrIcE.

JACOB HOWARD SNIVELY, OF SEATTLE, WASHINGTON.

X-RAY TUBE.

To all echo m. it may concern Be it known that I, JACOB I-IowARnSNIVELY, a citizen of the United States, residing at Seattle, in thecounty of King and State of IVashington, have invented a new and usefulImprovement in X-Ray Tubes, f which the following is a specification.

My invention relates to an improved apparatus or device to overcome thedifiici lty which has heretofore been experienced uring the use of theX-rays, withwhat are commonly called inverse, wild, secondary orVagabond rays which originate more or less from all portions of theX-ray tube and radiate in all directions, and cause blurring of theimage, streaks and indistinct outlines on the negative or fluoroscopicscreen. I overcome these difliculties by the use of the deviceillustrated in the accompanying drawing, in which- Figure 1 is a sideview of an ordinary form of X-ray tube fitted with my device andinclosed in the ordinary lead-glass protective shield. Fig. 2 is a sideview of an ordinary form of X-ray tube fitted with a little differentform of my device and not inclosed in a protective shield. Fig. 3 showsmy device separate from the tube.

Similar letters refer to similar parts throughout the several views.

In the operation of an Xray tube, the current is conducted through thevacuum tube by means of the electrodes or conductors a, e, and i, d, andduring the passage of the current particles of rarefied gases leave theconcave surface i in the form of converging cathode rays which meet atthe focus point E upolr'the face of the target or anode 6. Itis at thisfocus point E that the large quantity of X-rays are developed fromimpact of the cathode stream, and radiate in all directions, and it is aportion of these rays which it is desired to utilize and no others whichare generated in minor quantities from all other portions of the tube.It is these so called abnormal wild or Vagabond rays developed to someextent in all portions of the tube which blur the image formed by thedirect and evenly diverging rays radiating from the focus point E.

My invention consists of constructing Within the tube for generatingX-rays, a cone shaped device with the base to the Specification ofLetters Patent.

Patented Dec. 24, 1912-.

Application filed October 4, 1911. Serial No. 652,859..

most desirable portion of the circumference or wall 0 of the X-ray tubeand the apical opening it near and pointing toward the focus point E ofthe target (2. This cone shaped body I) to be made of some materialopaque to the X-rays such as lead-glass per haps capped with some metalatthe apex on account of the intense heat engendered at this point. Thevacuum of the cone 6 forms a part of the general vacuum in the main tubethrough the opening h.

The cone 6 may be attached to the wall 0 of the X-ray tube by glasshangers, or in order to provide for contraction and expansion or forother reasons it might be desirable to have the cone 1) constructed asshown in Fig. 2, extending through the wall of the X-ray tube, or thedevice I) might be shaped like a hollow pyramid or otherwise, the idea,however, being to provide an opaque conical shaped directing tube, theapex of which being placed as near as practicable to and pointing towardthe focus point of the cathode stream, and the hole or opening in theapex being so placed, so shaped and of a size to be most eflicient inadmitting the greatest number of normal X-rays radiating directly fromthe focus point of the cathode stream, and at the same time excludethegreatest number of abnormal rays of all kinds from all other parts'ofthe X-ray tube.

I am aware that X-ray tubes, screens, shields, diaphragms, etc., invarious combinations are in use, and do not claim my combinationbroadly: but

I claim:

1. In combination with an X-ray tube and located within said tube, aconical shaped device of lead glass capped with metal at the smallapical opening it, and with the apical opening h, close to and directedtoward the focus point E of the cathode stream on the face of the target0, and with the open base of the conical shaped device fastened to thewall a, of the Roentgen tube, substantially as shown and for thepurposes described.

2. In combination with an X-ray tube, a conical shaped device ofmaterial opaque to the X-rays, and with the small apical openingh,.close to and directed toward the focus point E of the cathode streamon the face of the target 2, and the opaqueconical device fastened tothe Wall 0, of the Roentgen signed my name in the presence of twowittube, the base of the opaque conical device 6, nesses.

being closed with transparent glass actin 1 as a portion of the Wall 0of the Roentgei l JALOB HOWARD SNIVELY' 5 tube, substantially as shownand for the \Vitnesses:

purposes described. ERNEST BERNARD HERALD,

In testimony whereof I have hereunto ERNEST AUGUST KLURZH.

